diff options
author | Vivek Goyal <vgoyal@redhat.com> | 2014-08-08 21:25:50 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-08 22:57:32 (GMT) |
commit | 8c86e70acead629aacb4afcd818add66bf6844d9 (patch) | |
tree | fbaa4e677b76cb8bfca7b21e9626a0607ca63c09 /kernel | |
parent | 255aedd90e3e804fb52e1a71636a3b22cf12f81b (diff) | |
download | linux-8c86e70acead629aacb4afcd818add66bf6844d9.tar.xz |
resource: provide new functions to walk through resources
I have added two more functions to walk through resources.
Currently walk_system_ram_range() deals with pfn and /proc/iomem can
contain partial pages. By dealing in pfn, callback function loses the
info that last page of a memory range is a partial page and not the full
page. So I implemented walk_system_ram_res() which returns u64 values to
callback functions and now it properly return start and end address.
walk_system_ram_range() uses find_next_system_ram() to find the next ram
resource. This in turn only travels through siblings of top level child
and does not travers through all the nodes of the resoruce tree. I also
need another function where I can walk through all the resources, for
example figure out where "GART" aperture is. Figure out where ACPI memory
is.
So I wrote another function walk_iomem_res() which walks through all
/proc/iomem resources and returns matches as asked by caller. Caller can
specify "name" of resource, start and end and flags.
Got rid of find_next_system_ram_res() and instead implemented more generic
find_next_iomem_res() which can be used to traverse top level children
only based on an argument.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/resource.c | 101 |
1 files changed, 92 insertions, 9 deletions
diff --git a/kernel/resource.c b/kernel/resource.c index 3c2237a..da14b8d 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -59,10 +59,12 @@ static DEFINE_RWLOCK(resource_lock); static struct resource *bootmem_resource_free; static DEFINE_SPINLOCK(bootmem_resource_lock); -static void *r_next(struct seq_file *m, void *v, loff_t *pos) +static struct resource *next_resource(struct resource *p, bool sibling_only) { - struct resource *p = v; - (*pos)++; + /* Caller wants to traverse through siblings only */ + if (sibling_only) + return p->sibling; + if (p->child) return p->child; while (!p->sibling && p->parent) @@ -70,6 +72,13 @@ static void *r_next(struct seq_file *m, void *v, loff_t *pos) return p->sibling; } +static void *r_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct resource *p = v; + (*pos)++; + return (void *)next_resource(p, false); +} + #ifdef CONFIG_PROC_FS enum { MAX_IORES_LEVEL = 5 }; @@ -322,16 +331,19 @@ int release_resource(struct resource *old) EXPORT_SYMBOL(release_resource); -#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) /* - * Finds the lowest memory reosurce exists within [res->start.res->end) + * Finds the lowest iomem reosurce exists with-in [res->start.res->end) * the caller must specify res->start, res->end, res->flags and "name". * If found, returns 0, res is overwritten, if not found, returns -1. + * This walks through whole tree and not just first level children + * until and unless first_level_children_only is true. */ -static int find_next_system_ram(struct resource *res, char *name) +static int find_next_iomem_res(struct resource *res, char *name, + bool first_level_children_only) { resource_size_t start, end; struct resource *p; + bool sibling_only = false; BUG_ON(!res); @@ -340,8 +352,14 @@ static int find_next_system_ram(struct resource *res, char *name) BUG_ON(start >= end); read_lock(&resource_lock); - for (p = iomem_resource.child; p ; p = p->sibling) { - /* system ram is just marked as IORESOURCE_MEM */ + + if (first_level_children_only) { + p = iomem_resource.child; + sibling_only = true; + } else + p = &iomem_resource; + + while ((p = next_resource(p, sibling_only))) { if (p->flags != res->flags) continue; if (name && strcmp(p->name, name)) @@ -353,6 +371,7 @@ static int find_next_system_ram(struct resource *res, char *name) if ((p->end >= start) && (p->start < end)) break; } + read_unlock(&resource_lock); if (!p) return -1; @@ -365,6 +384,70 @@ static int find_next_system_ram(struct resource *res, char *name) } /* + * Walks through iomem resources and calls func() with matching resource + * ranges. This walks through whole tree and not just first level children. + * All the memory ranges which overlap start,end and also match flags and + * name are valid candidates. + * + * @name: name of resource + * @flags: resource flags + * @start: start addr + * @end: end addr + */ +int walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end, + void *arg, int (*func)(u64, u64, void *)) +{ + struct resource res; + u64 orig_end; + int ret = -1; + + res.start = start; + res.end = end; + res.flags = flags; + orig_end = res.end; + while ((res.start < res.end) && + (!find_next_iomem_res(&res, name, false))) { + ret = (*func)(res.start, res.end, arg); + if (ret) + break; + res.start = res.end + 1; + res.end = orig_end; + } + return ret; +} + +/* + * This function calls callback against all memory range of "System RAM" + * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY. + * Now, this function is only for "System RAM". This function deals with + * full ranges and not pfn. If resources are not pfn aligned, dealing + * with pfn can truncate ranges. + */ +int walk_system_ram_res(u64 start, u64 end, void *arg, + int (*func)(u64, u64, void *)) +{ + struct resource res; + u64 orig_end; + int ret = -1; + + res.start = start; + res.end = end; + res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; + orig_end = res.end; + while ((res.start < res.end) && + (!find_next_iomem_res(&res, "System RAM", true))) { + ret = (*func)(res.start, res.end, arg); + if (ret) + break; + res.start = res.end + 1; + res.end = orig_end; + } + return ret; +} + +#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) + +/* * This function calls callback against all memory range of "System RAM" * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY. * Now, this function is only for "System RAM". @@ -382,7 +465,7 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; orig_end = res.end; while ((res.start < res.end) && - (find_next_system_ram(&res, "System RAM") >= 0)) { + (find_next_iomem_res(&res, "System RAM", true) >= 0)) { pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT; end_pfn = (res.end + 1) >> PAGE_SHIFT; if (end_pfn > pfn) |